16.2. The general information on search of malfunctions in electric chains

The typical electric chain consists of the electric component, switches, the relay, motors, safety locks, fusible inserts or breakers of a chain connected to this component and also conducting and sockets which connect a component with the battery and the chassis. To help you to reveal malfunction in an electric chain, at the end of this manual there are Schematic electric circuits.

Before undertaking any faulty electric chain, at first study its assembly diagram completely to understand what it consists of. For example, sometimes it is possible to narrow significantly the field of troubleshooting, having checked work of other components connected with this chain. If several components or chains failed at once, then, it is possible that a problem in safety locks or in grounding since often several chains pass through one connection of safety locks and wires of grounding.

Malfunctions in electric chains usually come from the simple reasons, such as easing or oxidation of contacts, the burned-down safety lock, the melted fusible insert or malfunction of the relay. Therefore before to begin search of damages, visually check a condition of all safety locks, wires and contacts in a faulty chain.

The main devices necessary for detection of malfunction in an electric chain, include a tester, the digital voltmeter with a high resistance, a tester of conductivity of a chain and a wire from a set for start of the car from an external source with the built-in breaker of a chain which is used for a round of components of a chain. Before trying to reveal malfunction by means of the testing devices, glance in the assembly diagram to define to what place to connect them.

Check of tension in a chain

An inspection of tension is carried out when the chain badly functions. Connect one end of a tester of a chain to a negative wire of the battery or to reliable grounding.

Connect other end to one of sockets of the tested chain, it is preferable to that which is the closest to the battery or to a safety lock. If the bulb of a tester burns, so in a chain there is tension that, in turn, means that on the site of a chain between the socket and the battery there is no malfunction. Continue to check the remained sites of a chain in the same way.

When you reach the site in which there is no tension, will find the place of malfunction. Most often the problem appears in bad contact.

Remember that in some chains tension arises, only when ignition is included.

Finding of malfunction in a chain - quite simple business if you remember that any electric chain is the electricity going from the battery on wires via switches, the relay, safety locks and fusible inserts to various components of an electric chain (bulbs, motors, etc.) and to the earth from which it passes back to the battery. And any malfunction in a chain is a violation of a stream of electricity from the battery or to the battery.

Search of the place of short circuit

One of methods of search of the place of short circuit in a chain is to disconnect a safety lock and to connect a test bulb or the voltmeter on its place. In a chain there should not be tension. Move an electrical wiring here and there, watching a test bulb. If the bulb joins, so on this site there is a short circuit on the earth probably somewhere isolation was wiped. Also each component of a chain is checked, up to the switch.

Grounding check

Carry out the test for grounding to check whether the chain component is correctly grounded. Disconnect the battery and connect one end of a tester of conductivity of a chain to reliable grounding. Connect other end to a wire or the socket of the checked grounding. If the bulb lights up, then grounding is made correctly. If does not light up, then it is wrong. In this case disconnect the socket and carefully clean all connecting details. Again connecting the socket, use whenever possible jagged washers and reliably tighten all bolts and other fixture.

If the radio receiver on your car is equipped with system of protection against theft, make sure that you gathered the correct code before disconnecting a battery wire. Apply for information in the Section System of Protection of the Audio System from theft and language of an instrument guard before a wire detachment.


If after accession of a wire on your instrument guard there were inscriptions not in that language which is necessary to you, address the Section System of Protection of the Audio System from theft and language of an instrument guard where the procedure of installation of the necessary language is described.

Check of conductivity of a chain

Check of conductivity of a chain is made to define whether is not present in a chain of breaks - whether well it carries current. For check the conductivity tester is used, current in a chain is switched off. Attach connecting wires to both ends of a chain and if the test bulb is lit, so the chain carries current well. If the bulb is not lit, then somewhere in a chain there is a break. The same procedure is used for check of the switch, only the tester of conductivity is connected to switch plugs. At the switched-on switch the bulb has to light up.

Search of disconnection in a chain

At visual definition of the place of possible disconnection of a chain often there are difficulties since oxidation or shift of contacts is hidden by sockets. Disconnection in a chain is often caused by oxidation or weakening of contacts. Having just moved contact of the socket on the perceiving element or in conducting, it is possible to restore the opened chain, at least temporarily. Disconnect the socket and spray it water from an aerosol barrel. On simple sockets sometimes it is possible to bend carefully contacts of the socket inside to improve contact - however be not fond of it not to damage the socket.